Frequent use of electrode tips for use in spot welding or the like causes deformation of tip sections of the electrode tips, thereby compelling stopping of welding operation. A tip shaping apparatus is known in Patent Literature 1 shaping electrode tips into reusable condition by applying plastic deformation to deformed tip sections of electrode tips rather than by cutting which would produce cutting or grinding swarf. The electrode tip used in Patent Literature 1 includes a columnar root section and a tip section, and the tip section includes a leading end surface that contacts with a workpiece and an enlarging surface that enlarges from the leading end surface toward the root section.
The above tip shaping apparatus is constructed to shape the leading end surfaces and the enlarging surfaces of electrode tips in order to correct changes of shape and area of the leading end surfaces due to abrasion or the like. To this end, the tip shaping apparatus includes a holder that is driven rotationally and is coaxial with axes of electrode tips coming close to each other, a plurality of shaping rollers held by the holder and each of which is provided with a shaping surface and a cutting section having a cutting blade that cuts vicinities of the leading end surfaces of electrode tips.
When the above tip shaping apparatus is used, a pair of electrode tips carried by a welding gun are moved toward the interior of the holder while being brought close to each other, and pressed against the shaping rollers and the cutting section. Then the shaping rollers rotate about the axes of the electrode tips together with the holder and apply the shaping surfaces to the tip sections of the electrode tips, thereby shaping the enlarging surfaces. In the meantime, the cutting section cuts the leading end surfaces and vicinities of edges of the leading end surfaces by the cutting blades. Thus the conventional tip shaping apparatus shapes the tip sections of electrode tips with high accuracy.